The present disclosure relates in general to computer systems with storage devices, and, more particularly, to a method and system for connecting dual, storage interfaces.
In personal computer systems, data is stored in many different media. There are a variety of devices capable of providing the data that is utilized by a computer""s processor. There are also a variety of interfaces that are used in a computer system to communicate with a storage device. The same interface may be used by different types of devices and different interfaces may be used by the same type of device.
As an example, both a hard drive and a CD reader may contain hardware for connecting to the processor using the integrated drive electronics (IDE) interface. Devices other than hard drives may use a protocol called ATA packet interface or ATAPI to connect to an IDE interface. But another hard drive may use the small computer systems interface (SCSI) instead of IDE. Additionally, each interface may also have subcategories. For example, a SCSI hard drive can have either an 8-bit bus or a 16-bit bus, sometimes referred to as wide SCSI.
Those variations in how storage devices communicate with the other major components of a computer system are addressed in a typical system by limiting the interfaces that can be used or by providing circuitry for multiple interfaces. One computer system may only allow the use of IDE drives unless an expansion card is provided for the SCSI interface. Another computer system may provide circuitry for multiple interfaces, using precious space on the motherboard. For example, a motherboard may include both an IDE controller and a 40-pin socket in order to provide an IDE interface. The controller sends and receives signals appropriate to the IDE interface to the IDE device through the 40-pin socket. That motherboard may also include a SCSI controller connected to a 50-pin socket in order to provide a SCSI interface. Such use of motherboard space to provide both IDE and SCSI functionality may preclude other components that are desired in the computer system. Another possibility is increasing costs by increasing the size of the moterhboard and the case necessary to hold it.
Standard IDE and SCSI controllers are inexpensive in comparison to custom-built controllers. Such standard controllers may be included as portions of multifunction chips. Allocating space for both SCSI and IDE sockets on a motherboard is wasteful when only one device will be used at a time. While the size of circuitry diminishes each year, the size of a standard IDE or SCSI socket has remained the same in order to comply with the physical standard. It is desirable that a motherboard have the capability to be used with either IDE or SCSI devices without sacrificing space needed for other functionality.
A method and system for connecting dual storage interfaces is disclosed that provides significant advantages over prior dual interface configurations. A computer system having the interface circuit allows flexible use of storage devices that are designed for either the IDE or SCSI interface while reducing use of motherboard space.
A computer system is provided that is capable of connecting to either an IDE or a SCSI device with a single socket or connector and without using an expansion slot. The computer system includes a motherboard with both IDE and SCSI controllers. The motherboard also includes a SCSI connector or socket. A cable is included in the computer system which can connect the SCSI socket to an IDE device. In a further enhancement, the cable may provide a third connection point for SCSI devices.
A more specific computer system is also provided in which a disconnect circuit is coupled between the IDE controller and the SCSI socket. The disconnect circuit only allows communication between the IDE controller and the SCSI socket when an IDE device has been detected.
A method is provided for connecting to multiple interfaces in which an IDE controller and a SCSI connector or socket are coupled to a motherboard. An IDE device is coupled to the SCSI connector. The electrical status of a pin of the IDE device is tested and, if it is at ground, communication is enabled between the IDE controller and the SCSI connector. A further enhancement of the method couples a SCSI controller to both the motherboard and the SCSI connector, and disables the SCSI controller when the tested pin is at ground.
It is a technical advantage of the disclosed methods and systems that both IDE and SCSI interface storage devices can communicate with other computer system components without committing motherboard space for two sockets or using an expansion slot. In this manner a computer system can retain storage device interface flexibility while reducing physical size.
Another technical advantage of the system and method disclosed is that it can utilize standard IDE and SCSI controllers. Such controllers are available both as separate integrated circuits and as part of multifunction chips. Other technical advantages of the present disclosure will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.